Sixteen-cornered strengthening member for vehicles

ABSTRACT

A strengthening member for a motor vehicle, the strengthening member has a cross section that comprises sixteen corners and includes sides and corners creating eight internal angles and eight external angles. Each internal angle ranges between about 90° and about 145° and each external angle ranges between about 95° and about 175°. One or more tunable parameters of a cross section can vary along a longitudinal axis of the strengthening member.

RELATED APPLICATION

This application is a Divisional of U.S. patent application Ser. No.14/749,426, filed on Jun. 24, 2015 (currently pending), the entirecontents of which is incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates generally to a strengthening member for avehicle body or other structures. The present disclosure relates morespecifically to a strengthening member having a sixteen-cornered crosssection and to motor vehicles including a strengthening member having asixteen-cornered cross section.

BACKGROUND

It is desirable, for vehicle strengthening members, to maximize impactenergy absorption and bending resistance while minimizing mass per unitlength of the strengthening member. Impact energy absorption may bemaximized, for example, by assuring that the strengthening membercompacts substantially along a longitudinal axis of the strengtheningmember upon experiencing an impact along this axis. Such longitudinalcompaction may be referred to as a stable axial crush of thestrengthening member.

When a compressive force is exerted on a strengthening member, forexample, by a force due to a front impact load on a vehicle's front railor other strengthening member in the engine compartment, thestrengthening member can crush in a longitudinal direction to absorb theenergy of the collision. In addition, when a bending force is exerted ona strengthening member, for example, by a force due to a side impactload on a vehicle's front side sill, B-pillar or other strengtheningmember, the strengthening member can bend to absorb the energy of thecollision.

Conventional strengthening members rely on increasing the thickness andhardness of side and/or corner portions to improve crush strength.However, such increased thickness and hardness increases weight of thestrengthening member and reduces manufacturing feasibility. It may bedesirable to provide a strengthening assembly configured to achieve thesame or similar strength increase as provided by the thickened sidesand/or corners, while minimizing mass per unit length of the member, andmaintaining a high manufacturing feasibility.

It may further be desirable to provide a strengthening member that canachieve increased energy absorption and a more stable axial collapsewhen forces such as front and side impact forces are exerted on thestrengthening member, while also conserving mass to reduce vehicleweights and meet emission requirements. Also, it may be desirable toprovide a strengthening member that can achieve improved energyabsorption and bend when a bending force is exerted on the strengtheningmember. Additionally, it may be desirable to provide a strengtheningmember that possesses improved noise-vibration-harshness performance dueto work hardening on its corners. In addition, it may be desirable, toprovide a tunable strengthening member cross section configured toachieve strength increases (i.e., load carrying and energy absorption)over basic polygonal designs, while also allowing flexibility in designto meet a range of vehicle applications.

SUMMARY

In accordance with various exemplary embodiments of the presentdisclosure, a strengthening member for a motor vehicle is provided. Thestrengthening member has a sixteen-cornered cross section comprisingsixteen corners and including sides and corners creating eight internalangles and eight external angles. Each internal angle ranges betweenabout 90° and about 145°. Each external angle ranges between about 95°and about 175°.

In accordance with another aspect of the present disclosure, astrengthening member for a motor vehicle comprises a cross sectioncomprising sixteen corners and including sides and corners creatingeight internal angles and eight external angles. The strengtheningmember has a longitudinal axis, and the strengthening member tapersalong the longitudinal axis.

In accordance with a further aspect of the present disclosure, a vehiclecomprises a strengthening member. The strengthening member comprises asixteen-cornered cross section including sixteen corners and includingsides and corners creating eight internal angle corners and eightexternal angle corners.

Additional objects and advantages will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or may be learned by practice of the present teachings. Theobjects and advantages of the present disclosure will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the claimed subject matter. The accompanyingdrawings, which are incorporated in and constitute part of thisspecification, illustrate exemplary embodiments of the presentdisclosure and together with the description, serve to explainprinciples of the present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

At least some features and advantages of the present teachings will beapparent from the following detailed description of exemplaryembodiments consistent therewith, which description should be consideredwith reference to the accompanying drawings, wherein:

FIG. 1 illustrates an exemplary embodiment of a sixteen-cornered crosssection of a strengthening member, with the strengthening member havingeight internal angles and eight external angles in accordance with thepresent teachings;

FIGS. 2A-2B illustrate top and perspective views of a first exemplaryembodiment of a strengthening member having a sixteen-cornered crosssection, with eight internal angles and eight external angles, as shownin FIG. 1;

FIGS. 3A-3B illustrate top and perspective views of a second exemplaryembodiment of a strengthening member having sixteen-cornered crosssections, with eight internal angles and eight external angles inaccordance with the present teachings;

FIGS. 4A-4B illustrate top and perspective views of a third exemplaryembodiment of a strengthening member having sixteen-cornered crosssections, with eight internal angles and eight external angles inaccordance with the present teachings;

FIGS. 5A-5B illustrate top and perspective views of a fourth exemplaryembodiment of a strengthening member having sixteen-cornered crosssections, with eight internal angles and eight external angles inaccordance with the present teachings;

FIGS. 6A-6B illustrate top and perspective views of a fifth exemplaryembodiment of a strengthening member having sixteen-cornered crosssections, with eight internal angles and eight external angles inaccordance with the present teachings;

FIG. 7 illustrates strengthening members of various cross sectionshaving substantially the same thickness, substantially the longitudinallength, and cross-sectional dimensions along perpendicularly orientedtransverse axes with substantially the same lengths;

FIG. 8 illustrates an exemplary quasi-static axial collapse of thestrengthening members shown in FIG. 7;

FIG. 9 illustrates an exemplary dynamic crush of the strengtheningmembers shown in FIG. 7;

FIG. 10 is a graph of the dynamic crush force and associated crushdistance for the exemplary strengthening members shown in FIG. 7;

FIG. 11 is a graph of the dynamic axial crush energy and associatedaxial crush distance for the exemplary strengthening members shown inFIG. 7;

FIG. 12 illustrates sixteen-cornered strengthening members of varyingcross-sectional shapes, each cross-section having sides withsubstantially the same thickness, substantially the same longitudinallength, and cross-sectional dimensions along perpendicularly orientedtransverse axes with substantially the same lengths;

FIG. 13 illustrates an exemplary quasi-static axial collapse of thestrengthening members shown in FIG. 12;

FIG. 14 illustrates an exemplary dynamic crush of the strengtheningmembers shown in FIG. 12;

FIG. 15 is a graph of the dynamic crush force and associated axial crushdistance for exemplary strengthening members having the cross sectionsshown in FIG. 12;

FIG. 16 is a graph of the dynamic axial crush energy and associatedaxial crush distance for exemplary strengthening members having thecross sections shown in FIG. 12;

FIG. 17 illustrates an exemplary embodiment of a vehicle frame withseveral components for which a strengthening member havingsixteen-cornered cross sections, with eight internal angles and eightexternal angles can be used; and

FIG. 18 illustrates an exemplary embodiment of a vehicle upper body withseveral components for which a strengthening member havingsixteen-cornered cross sections, with eight internal angles and eightexternal angles can be used.

Although the following detailed description makes reference to exemplaryillustrative embodiments, many alternatives, modifications, andvariations thereof will be apparent to those skilled in the art.Accordingly, it is intended that the claimed subject matter be viewedbroadly.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference will now be made in detail to various exemplary embodiments,examples of which are illustrated in the accompanying drawings. Thevarious exemplary embodiments are not intended to limit the disclosure.To the contrary, the disclosure is intended to cover alternatives,modifications, and equivalents of the exemplary embodiments. In thedrawings and the description, similar elements are provided with similarreference numerals. It is to be noted that the features explainedindividually in the description can be mutually combined in anytechnically expedient manner and disclose additional embodiments of thepresent disclosure.

The present teachings contemplate strengthening members withsixteen-cornered cross sections having substantially increased stiffnessthroughout the sides and corners without increasing thickness within thecorners as done in conventional strengthening members. The strengtheningmembers of the present disclosure are designed based in part on, forexample, a variety of tunable parameters configured to achieve strengthincreases (i.e., load carrying and energy absorption) over basicpolygonal designs (e.g., polygonal strengthening member cross sectionshaving less or the same number of sides), while also allowing designflexibility to meet a range of vehicle applications.

In accordance with the present teachings, the shape of the strengtheningmembers disclosed herein provides the strengthening member withstabilized folding, reduced crush distance, and increased energyabsorption in response to an axially applied crash force. The shape alsoimproves moisture shedding abilities of the strengthening member andpermits a more customized fit with other vehicle components.

The strengthening members in accordance with the present teachings canachieve increased energy absorption and a more stable axial collapsewhen forces such as front and side impact forces are exerted on thestrengthening member. Furthermore, the side lengths and configurations,and/or degrees of the internal and external angles, of the strengtheningmembers in accordance with the present teachings can achieve a similar,if not greater, strength increase as thickened corners, while minimizingmass per unit length of the member and maintaining a high manufacturingfeasibility because the member can be formed by stamping, bending, pressforming, hydro-forming, molding, casting, extrusion, uniform ornon-uniform roll forming, machining, forging, and/or other knownmanufacturing processes. Thus-formed sections can be joined via welding,brazing, soldering, adhesive bonding, fastening, press fitting or otherknown joining technologies.

Strengthening members in accordance with the present teachings cancomprise, for example, traditional steels, advanced high strength steels(AHSS), ultra high strength steels (UHSS), new/next generation highstrength steels (NGHSS), titanium alloys, aluminum alloys, magnesiumalloys, nylons, plastics, composites, hybrid materials or any othersuitable materials. Those of ordinary skill in the art would understand,for example, that the material used for a strengthening member may bechosen based at least in part on intended application, strength/weightconsiderations, cost, packaging space, and/or other design factors.

An exemplary embodiment of a sixteen-cornered cross section of astrengthening member 100 in accordance with the present teachings isillustrated in FIG. 1. The strengthening member 100 has sixteen sides.The illustrated cross section of the strengthening member 100 comprisessixteen sides having lengths S₁-S₁₆ and thicknesses T₁-T₁₆, eightinternal corners with angles and eight external corners with anglesϑ_(e1)-ϑ_(e8).

The perimeter of the sixteen-sided cross section generally forms apolygon comprising a plurality of internal and external corners. Asembodied herein and shown in FIG. 1, the polygon may be formed ofalternating internal and external angles, and in particular, may beformed by alternating two consecutive internal corners/angles with twoconsecutive external corners/angles. This repeating pattern, whichalternates between two consecutive internal corners/angles and twoconsecutive external corners/angles (i.e., an alternating two-in-two-outconfiguration), results in a cross section with up to four bisectingplanes of symmetry. Under an axial and symmetric loading condition,strengthening members with symmetrical, polygonal cross sections,including the various embodiments of the present teachings, may havebetter load carrying capabilities and energy absorbing capabilities thanthose with asymmetrical, polygonal cross sections with an equivalentnumber of corners and sides. Furthermore, strengthening members withsymmetrical, polygonal cross sections with more than two bisectingplanes of symmetry (e.g., three bisecting planes of symmetry, orfour-or-more bisecting planes of symmetry), including the variousembodiments of the present teachings, may have better load carryingcapabilities and energy absorbing capabilities than those withsymmetrical, polygonal cross sections with two or fewer bisecting planesof symmetry and an equivalent number of corners and sides. However, asthose of skill in the art will understand, use of asymmetricalcross-sections may offer other benefits that provide advantages thatcannot be realized using a symmetrical cross-section. The presentdisclosure contemplates that a sixteen-sided, sixteen-corneredcross-section, in accordance with the present teachings, may be eithersymmetrical or asymmetrical.

Depending upon the particular application and/or the desired features ofthe strengthening member, the lengths of the sides and the thicknessesof the sides of the sixteen-sided, sixteen-cornered strengthening memberas well as the internal and external corner angles of the strengtheningmember can be varied (i.e., can be tuned) to achieve improved strengthand other performance features (e.g., stability of folding pattern)compared to conventional strengthening member cross sections. Varyingthese features of the sixteen-sided, sixteen-cornered strengtheningmember may obviate the need for increased side and/or corner thickness.In accordance with various exemplary embodiments of the presentteachings, the lengths of sides S₁-S₁₆, the thicknesses T₁-T₁₆ of thesides as well as the internal angles ϑ_(i1)-ϑ_(i8) and external anglesϑ_(e1)-ϑ_(e8) of the corner angles can be varied to a certain degree, aswould be understood by one skilled in the art, for example in accordancewith available packaging space within a vehicle.

In addition, in a strengthening member in accordance with the presentteachings, each internal corner angle ϑ_(i1)-ϑ_(i8) of the strengtheningmember can range from about 90° to about 145°, and each external cornerangle ϑ_(e1)-ϑ_(e8) of the strengthening member can range from about 95°to about 175°. In accordance with the present teachings, the internalangles ϑ_(i1)-ϑ_(i8) of the strengthening member may all besubstantially the same, and similarly, the external angles ϑ_(e1)-ϑ_(e8)of the strengthening member may all be substantially the same.Additionally, the present teachings contemplate embodiments for whichone, some, or all of the internal angle(s) ϑ_(i1)-ϑ_(i8) are rightangles. Additionally or alternatively, the present disclosurecontemplates embodiments in which at least some of the internal anglesϑ_(i1)-ϑ_(i8) of the strengthening member differ from one another, andsimilarly, at least some of the external angles ϑ_(e1)-ϑ_(e8) of thestrengthening member differ from one another. FIG. 1 illustrates anexemplary embodiment in which all of the internal angles ϑ_(i1)-ϑ_(i8)are about 90°, all of the external corner angles ϑ_(e1)-ϑ_(e8) are about135°, and the aspect ratio is 1:1.

In certain exemplary embodiments of the present disclosure, such as inan automotive application, for example, a length of each side S₁-S₁₆ ofthe strengthening member can range from about 10 mm to about 250 mm. Inother exemplary embodiments, such as in an aircraft, spacecraft,watercraft, or building application, for example, a length of each sideS₁-S₁₆ of the strengthening member may be larger.

In certain exemplary embodiments of the present disclosure, such as inan automotive application, for example, a thickness T₁-T₁₆ of the sidesof the strengthening member can range from about 0.6 mm to about 6.0 mm.In other exemplary embodiments of the strengthening member, such as inan aircraft, spacecraft, watercraft, or building application, forexample, a thickness T₁-T₁₆ of the sides of the strengthening member maybe larger. In one exemplary embodiment, a thickness T₁-T₁₆ of each ofthe sides of the strengthening member may be about 3.3 mm. In anotherexemplary embodiment, a thickness T₁-T₁₆ of each of the sides may beabout 2.3 mm. In another exemplary embodiment, a thickness T₁-T₁₆ ofeach of the sides may be about 2.2 mm. In some exemplary embodiments,the thickness T₁-T₁₆ of the sides is substantially the same as thethickness of the corners for each side. In some exemplary embodimentsthe thickness T₁-T₁₆ of each side wall, (e.g., side walls 202A-202P (seeFIG. 2A)), can vary with respect to each other side wall. Alternativelyor concurrently, the thickness T₁-T₁₆ can vary within each length of thesides S₁-S₁₆.

Top and perspective views of a first exemplary embodiment of astrengthening member 200 having a sixteen-cornered cross section, witheight internal angles and eight external angles are illustrated in FIGS.2A-2B. Strengthening member 200 has sixteen corners 204A-H and 206A-Hand sixteen side walls 202A-202P. Eight of the corners are internalangle corners 204A-204H and eight of the corners are external anglecorners 206A-206H. Strengthening member 200 also has a first transverseaxis 208, a second transverse axis 210, and a longitudinal axis 212.Although shown with its longitudinal axis 212 positioned substantiallyvertically, when strengthening member 200 (as well as all of the othervarious embodiments in accordance with the present teachings) isinstalled within a vehicle, the longitudinal axis 212 of thestrengthening member may be oriented substantially horizontally. Wheninstalled in such a position, the shape of strengthening member 200facilitates reducing or preventing moisture collecting or pooling alongportions of the walls of the strengthening member. For example, certainconventional strengthening members whose walls form adjacent externalangles of 90 degrees or form rectangular, square, or u-shaped recessesor depressions may collect moisture or permit moisture to pool in therecesses, increasing the possibility of weakening of the strengtheningmember via rusting, stripping, cracking, etc. (i.e., any form ofoxidation or other chemical or physical distortion which the material ofmanufacture of the strengthening member may be more susceptible to dueto the presence of moisture).

In contrast, a strengthening member formed in accordance with thepresent teachings does not include a recessed portion in which liquidsor moisture remain for a long period of time. In particular, the wallsof the strengthening member are angled relative to one another topromote shedding of any moisture or fluid that falls within any recessedportion of the strengthening member. For example, as shown in FIGS. 2Aand 2B, strengthening member 200 includes a first recessed portion 214between side walls 202A and 202C. However, side walls 202A and 202C areconnected by a sloped/angled side wall 202B in such a manner that fluidimpinging or collecting on side wall 202B will run off side wall 202Band toward the ends of side wall 202A or 202C. Similarly, for example,as shown in FIGS. 2A and 2B, strengthening member 200 includes secondrecessed portion 215 between side walls 202E and 202G, third recessedportion 216 between side walls 2021 and 202K, and fourth recessedportion 217 between side walls 202M and 2020.

The strengthening member 200 of FIGS. 2A-2B also has a uniform crosssection along a length of the strengthening member 200, from a first end218 to a second end 220 of the strengthening member 200. Additionally,the length of each side S₁-S₁₆ is approximately the same as illustratedin FIGS. 2A-2B. As also illustrated, each of the internal angles issubstantially the same and each of the external angles is substantiallythe same. In particular, each internal angle is about 90° and eachexternal angle is about 135°. The thicknesses of each sidewall 202A-202Pare also substantially the same.

Top and perspective views of an alternative exemplary embodiment of astrengthening member 300 having a sixteen-cornered cross section, witheight internal angles and eight external angles, are illustrated inFIGS. 3A-3B. Strengthening member 300 differs from strengthening member200 in several aspects. For example, as shown in FIGS. 3A and 3B, one ormore of the side walls of the strengthening member may be angled withrespect to the longitudinal axis 312 of the strengthening member toprovide a taper to at least a portion of the shape of the strengtheningmember 300. As shown in FIGS. 3A-3B, strengthening member 300 is taperedalong its length, from a first end 318 of the strengthening member 300to a second end 320 of the strengthening member. The strengtheningmember 300 tapers along its length at an angle α, which can range fromabout 1° to about 65°. The degree of taper of each side wall may besubstantially the same, or different side walls may exhibit differingdegrees of taper. Tapering may be required due to component packagingconstraints and/or to effectively couple, attach or otherwise bond othercomponents to a strengthening member.

In the exemplary embodiment of FIGS. 3A-3B, all of the internal anglesϑ_(i) are about 90° and all of the external angles ϑ_(e) are about 135°.Also, as shown in FIGS. 3A-3B, strengthening member 300 includesrecessed areas 314, 315, 316 and 317. Each recessed area 314, 315, 316and 317 extends along the length of the strengthening member 300 fromfirst end 318 to second end 320. In the disclosed exemplary embodimentof FIGS. 3A-3B, the lengths of the sides S₁-S₁₆ are each approximatelythe same as the other sides when taken at any cross section along thelongitudinal length of the strengthening member 300. However, the lengthof each side gradually/incrementally increases along the longitudinalaxis 312 of the strengthening member 300 from first end 318 to secondend 320 to provide the tapered shape. As noted above, the embodiment ofFIGS. 3A-3B is exemplary, and therefore all of the contemplatedembodiments with variations to the lengths and thicknesses of the sidesand to the angles of the internal and external corner angles of thesixteen-cornered cross sections, with eight internal angles and eightexternal angles, of the strengthening members in accordance with thepresent teachings are not shown in the figures, but based on theteachings herein, will be apparent to those of skill in the art.

Top and perspective views of an alternative exemplary embodiment of astrengthening member 400 having the sixteen-cornered cross section, witheight internal angles and eight external angles, are illustrated inFIGS. 4A-4B. Similar to the strengthening member 300, strengtheningmember 400 tapers along its longitudinal axis 412 from a first end 418of the strengthening member to a second end 420 of the strengtheningmember. However, as shown in FIGS. 4A-4B, strengthening member 400differs from strengthening members 200 and 300 in that thedimension-to-dimension ratio of the cross section of the strengtheningmember, taken along transverse axes 408, 410 is not 1:1; rather, theaspect ratio is about 6.5:10.0. FIGS. 4A-4B illustrate a strengtheningmember that has a first length 422 along a first (minor) transverse axis408 and a second length 424 along a second (major) transverse axis 410,where the second transverse axis is perpendicular to the firsttransverse axis. The aspect ratio of a strengthening member may bedefined as [first length 422]:[second length 424]. In the exemplaryembodiment of FIGS. 4A-4B, all of the internal corner angles are aboutthe same, e.g., about 90°. In contrast, the external angles are not allsame. In particular, as shown in FIG. 4A, external angles each of theexternal angles ϑ_(e1), ϑ_(e4), ϑ_(e5), and ϑ_(e8) have a firstmeasurement, for example, about 123.5°, while external angles ϑ_(e2),ϑ_(e3), ϑ_(e6), and ϑ_(e7) have a second measurement, for example, about145.5°. As also shown, the sides of the strengthening member 400 havediffering lengths. Also, the strengthening member 400 of the exemplaryembodiment shown in FIGS. 4A-4B includes recessed areas 414, 415, 416and 417 spaced around the perimeter of the strengthening member andextending along the length of the strengthening member 400, eachrecessed area 414-417 extending from first end 418 to second end 420 ofstrengthening member 400. As noted above, the embodiment of FIGS. 4A-4Bis exemplary, and therefore all of the contemplated embodiments withvariations to the lengths of the sides, thicknesses of the sides, theangles of the internal and external corner angles, and the aspect ratioof the of the sixteen-cornered cross sections, with eight internalangles and eight external angles, of the strengthening members inaccordance with the present teachings are not shown in the figures.

Top and perspective views of an alternative exemplary embodiment of astrengthening member 500 having the sixteen-cornered cross section, witheight internal angles and eight external angles, are illustrated inFIGS. 5A-5B. In the exemplary embodiment of FIGS. 5A-5B, each of theinternal angles is about 90° and each of the external angles is about135°. As illustrated in FIG. 5A, the lengths of side walls 502B, 502F,502J, and 502N are greater in comparison to the lengths of side walls502A, 502C-E, 502G-I, 502K-M, 502O and 502P. This difference in thelengths of the sides provides recessed areas 514, 515, 516 and 517, eachof which extends along the length of the strengthening member 500 fromfirst end 518 to second end 520 of the strengthening member. Theserecessed areas 514-517 each have a depth δ₅₁₄-δ₅₁₇, which is reduced(and may be considered relatively shallow) in comparison to the recessedareas shown in the strengthening members illustrated in FIGS. 2A-4B.This type of parameter tuning, i.e., changing the lengths of the sidesto reduce the depth of the recess areas 514-517, can further improve themoisture shedding ability of the strengthening member 500. Inparticular, the combination of the decreased depth of the recessed areaand the increased length of the sloped wall (floor) of the recessed areawork together to direct moisture out of the recessed areas 514-517.

Top and perspective views of an alternative exemplary embodiment of astrengthening member 600 having the sixteen-cornered cross section, witheight internal angles and eight external angles, are illustrated inFIGS. 6A-6B. The strengthening member 600 of FIGS. 2A-2B has a uniformcross section along a longitudinal axis 612 of the strengthening member600, from a first end 618 to a second end 620 of the strengtheningmember 200. The thickness of each sidewall 602A-602P is alsosubstantially the same to each other side wall 602A-602P and throughoutthe longitudinal length of each side wall 602A-602P. However, thelengths of each side S₁-S₁₆ of each side wall 602A-602P are not all thesame. For example, as shown in FIG. 6A, the cross-sectional lengthsS_(j) of side walls 602A, 602C, 602E, 602G, 602I, 602K, 602M and 602Oare all substantially the same, however, they are different than thecross-sectional lengths S_(j) of side walls 602B, 602F, 602J and 602N.Further, 602B, 602F, 602J and 602N are all substantially the same crosssectional length S_(j), however the cross sectional lengths S; aredifferent than those of 602D, 602H, 602L and 602P. The strengtheningmember 600 includes eight internal angles ϑ_(i1)-ϑ_(i8) and eightexternal angles ϑ_(e1)-ϑ_(e8). As shown in FIGS. 6A-6B, each of theinternal angles is about 105° and each of the external angles is about150°. In addition, and in contrast to the strengthening member 500 shownin FIGS. 5A-5B, the lengths of side walls 602B, 602F, 602J, and 602N areshorter in comparison to the lengths of side walls 602A, 602C-E, 602G-I,602K-M, 602O and 602P. This difference in the lengths of the sidesprovides recessed areas 614-617, each of which extends along the lengthof the strengthening member 600 from first end 618 to second end 620 ofthe strengthening member 600. These recessed areas 614-617 have a depthδ₆₁₄-δ₆₁₇, respectively, which is increased (and may be consideredrelatively deep) in comparison to the recessed areas shown in thestrengthening members illustrated in FIGS. 5A-5B. However, the increaseddepth of the recessed areas 614-617 may be compensated for by varyingthe internal and external angles of the strengthening member crosssection. For example, as shown in FIGS. 6A-6B, increasing the internalangles to larger than 90 degrees results in a recessed area 614 in whichall walls of the recessed portion are sloped. This configurationincreases the ability of the recessed areas 614-617 of the strengtheningmember to shed moisture.

More generally, the various exemplary embodiments of the presentteachings contemplate, for example, strengthening members with cornershaving different bend radii, with non-uniform cross sections, havingnon-symmetrical shapes, with sides having variable thicknesses, and/orhaving variable tapered sides. Various additional exemplary embodimentscontemplate strengthening members that are bent and/or curved. Moreover,to further adjust a member's folding pattern and/or peak load capacity,various additional exemplary embodiments also contemplate strengtheningmembers having trigger holes, flanges, and/or convolutions as would beunderstood by those of ordinary skill in the art. Combinations of one ormore of the above described variations are also contemplated.

As discussed and embodied herein, the lengths S₁-S₁₆ and thicknessesT₁-T₁₆ of the sides of the strengthening member are tunable parametersof the strengthening member. The lengths S₁-S₁₆ and thicknesses T₁-T₁₆of the sides may be tuned to provide desired characteristics in thestrengthening member. For example, in the embodiment of FIGS. 3A-3B,these parameters are tuned to provide a strengthening member 300 withside walls and corners that are tapered along the longitudinal length ofthe strengthening member 300.

As discussed and embodied herein, the aspect ratio of a cross section ofthe strengthening member is a tunable parameter in accordance with thepresent teachings. The aspect ratio of a cross section of astrengthening member may be tuned to provide desired characteristics inthe strengthening member. For example, in the embodiment of FIGS. 4A-4B,these parameters are tuned to provide a strengthening member 400 havingtwo cross-sectional dimensions along perpendicularly oriented transverseaxes that are substantially different in length the longitudinal lengthof the strengthening member 400.

As discussed and embodied herein, the lengths of the sides S₁-S₁₆ of thecross section is a tunable parameter in accordance with the presentteachings. The lengths of the sides S₁-S₁₆ of a strengthening member maybe tuned to provide desired characteristics in the strengthening member.For example, in the embodiment of FIGS. 5A-5B this parameter is tuned toprovide a strengthening member 500 with recess areas 514-517 havingparticular depths δ₅₁₄-δ₅₁₇ that extend along the longitudinal length ofthe strengthening member 500.

As discussed and embodied herein, the eight internal anglesϑ_(i1)-ϑ_(i8) and eight external angles ϑ_(e1)ϑ_(e8) are tunableparameters of the strengthening member. The internal anglesϑ_(i1)-ϑ_(i8) and external angles ϑ_(e1)-ϑ_(e8) may be tuned to providedesired characteristics in the strengthening member. For example, in theembodiment of FIGS. 6A-6B, these parameters are tuned to provide astrengthening member 600 with sloped recessed areas 614-617 having aparticular depths δ₆₁₄-δ₆₁₇ that extend along the longitudinal length ofthe strengthening member 600.

As discussed and embodied herein, multiple tunable parameters—includingbut not limited to the lengths S₁-S₁₆ and thicknesses T₁-T₁₆ of thesides of the strengthening member, the aspect ratio of a cross sectionof the strengthening member, the internal angles ϑ_(i1)-ϑ_(i8) andexternal angles ϑ_(e1)ϑ_(e8) of the corners, and the depths δ_(j14-j17)of the recess areas—may all be tuned within the same strengtheningmember. These parameters all may be tuned within the same strengtheningmember to provide desired characteristics in the strengthening member.

In the illustrated embodiments of FIGS. 2A-6B, the strengthening membersmay have a one-piece construction. As stated above, the one-piececonstructions shown in FIGS. 2A through 6B are exemplary only and thepresent teachings contemplate strengthening members of otherconstructions such as two-piece construction or even three-or-more piececonstruction.

To demonstrate the improved strength and performance features of asixteen-cornered cross section having eight internal angles and eightexternal angles in accordance with the present teachings, the inventorscompared various existing and conventional strengthening member crosssection designs to cross sections based on the designs disclosed herein.Exemplary strengthening members were modeled and crash simulation runswere conducted, as shown and described below with reference to FIGS.7-11.

Strengthening members of varying shapes (i.e., cross sections) havingthe same mass, thickness, longitudinal length and the samecross-sectional lengths along perpendicular transverse axes were modeledas illustrated in FIG. 7. Crash simulations were then run for eachmember to simulate an impact with the same rigid mass (e.g., animpactor), impact speed, and initial kinetic energy.

FIG. 8 shows cross members which have undergone a simulated quasi-staticcrush. During each quasi-static crush the impact speed is slow (e.g., 1in/min). An impactor compresses the members with a controlleddisplacement. Therefore, all members reach the same crush distance withthe same crush time. Thus, subjecting multiple strengthening members toa quasi-static crush provides a comparison of the folding length and thecrush stability of the strengthening members. As shown in FIG. 8, thesixteen-cornered cross section in accordance with the present teachingsdemonstrated the most stable axial collapse and the smallest foldinglength.

FIG. 9 shows cross members which have undergone a simulated dynamiccrush. During each dynamic crush, the impactor is propelled by a gas gunwith a designated mass and initial impact velocity which creates adesignated initial kinetic energy. The initial kinetic energy crushesthe members. Performance of each strengthening member can be compared bymeasuring the crush distance and specific energy absorption of eachstrengthening member. As shown in FIG. 9, the sixteen-cornered crosssection in accordance with the present teachings also demonstrated theshortest crush distance.

FIG. 10 illustrates the dynamic crush force (in kN) and associated axialcrush distance (in mm) for the simulated dynamic crush, exerted axiallyon the exemplary strengthening members having the cross sections shownin FIG. 7. As shown in FIG. 10, the strengthening member having asixteen-cornered cross section could sustain a much higher crushingforce for a given resulting crushing distance as compared with thesquare, hexagonal, circular, octagonal, and twelve-cornered crosssections. Specifically, the sixteen-cornered cross section in accordancewith the present teachings achieved about a 65% increase in averagedcrush force and/or crash energy absorption as compared with the octagon.

FIG. 11 illustrates the dynamic axial crush energy (in kN-mm) andassociated axial crush distance (in mm) for a simulated dynamic crushexerted on the exemplary strengthening members having the cross sectionsshown in FIG. 7. As shown in FIG. 11, the strengthening member having asixteen-cornered cross section could absorb the same total kineticenergy of the impact over a much shorter distance as compared with thesquare, hexagonal, circular and octagonal cross sections. In particular,a sixteen-cornered cross section in accordance with the presentteachings absorbed the full axial crush energy in about 60% of the axialcrush distance as the basic octagonal cross section.

To further demonstrate the improved strength and performance features ofa sixteen-cornered cross section in accordance with the presentteachings compared to basic sixteen-sided cross section designs,exemplary strengthening members were modeled and crash simulation runswere conducted, as shown and described below with reference to FIGS.12-16.

Strengthening members of varying shapes (i.e., sixteen-sided crosssections) having the same thickness, longitudinal length and the samecross-sectional lengths along perpendicular transverse axes were modeledas illustrated in FIG. 12. As above, tests were then run for each memberto simulate a quasi-static collapse and a dynamic crush with the samerigid mass (e.g. an impactor), impact speed, and initial kinetic energy.As shown in FIG. 13 for the quasi-static collapse, the sixteen-corneredcross section in accordance with the present teachings demonstrated themost stable axial collapse and smallest folding length. Furthermore, asshown in FIG. 14 for the dynamic crush, the sixteen-cornered crosssection in accordance with the present teachings also demonstrated theshortest crush distance.

FIG. 15 illustrates the dynamic crush force (in kN) and associated axialcrush distance (in mm) for the simulated dynamic crush, exerted axiallyon the exemplary strengthening members having the cross sections shownin FIG. 12. As shown in FIG. 15, once again, the strengthening memberhaving a sixteen-cornered cross section in accordance with the presentteachings could sustain a much higher crushing force for a givenresulting crushing distance as compared with the other sixteen-sidedcross sections (i.e., the basic sixteen-sided polygon (hexadecagon) andsixteen-sided corrugated polygon). In fact, the sixteen-cornered crosssection in accordance with the present teachings achieved about a 75%increase in averaged crush force and/or crash energy absorption ascompared with the hexadecagon.

FIG. 16 illustrates the axial crush energy (in kN-mm) and associatedaxial crush distance (in mm) for a simulated dynamic crush exerted onthe exemplary strengthening members having the cross sections shown inFIG. 12. As shown in FIG. 16, once again, the strengthening memberhaving a sixteen-cornered cross section in accordance with the presentteachings could absorb the same total kinetic energy of the impact overa much shorter crush distance as compared with the other sixteen-sidedcross sections. In fact, the sixteen-cornered cross section inaccordance with the present teachings absorbed the full axial crushenergy in about 57% of the axial crush distance as the hexadecagon.

Sixteen-cornered cross sections in accordance with the present teachingsmay, therefore, allow improved impact energy management over, forexample, basic polygonal strengthening member cross sections, includingbasic sixteen-sided polygonal cross sections, while minimizing mass perunit length, provides mass saving solutions that reduce vehicle weightand meet new CAFE and emission standards.

Beyond the increased load carrying and energy absorption capabilities,strengthening members in accordance with the present teachings mayprovide additional advantages or benefits such as improved moistureshedding abilities (as noted above), increased bending energy absorptioncapacity, improved manufacturing feasibility, and better fitting of theshape amongst the other components of the complete device (e.g.,vehicle).

In addition, a sixteen-cornered strengthening member in accordance withthe present teachings also may be tuned to accommodate unique packagingrequirements for use in various vehicles. By virtue of the particularshape of the cross section of at least some of the sixteen corneredcross members, it may be easier to couple, bond, attach, or otherwiseaffix other device components to the strengthening member. Other devicecomponents can include, but are not limited to, engine mounts ortransmission mounts.

Sixteen-cornered strengthening members in accordance with the presentteachings are contemplated for use as structural members in a number ofenvironments. For example, in a motor vehicle, a strengthening member asdisclosed herein may be used, for example, as one or more of crush cans,front rails, mid-rails, rear rails, side rails, shotguns, cross members,roof structures, beltline tubes, door beams, pillars, internalreinforcements, and other components that can benefit from increasedcrash energy absorption or the other advantages described herein. Inaddition, the present teachings can be applied to both body-on-frame andunitized vehicles, or other types of structures.

For example, as shown in FIGS. 17 and 18, sixteen-cornered strengtheningmembers with eight internal angles and eight external angles inaccordance with the present disclosure can be used to form part of orwithin a vehicle frame and/or a vehicle upper body. FIG. 17 illustratesan exemplary embodiment of a vehicle frame 1700 with several componentsfor which the strengthening can be used. For example, the strengtheningmembers in accordance with the present invention may form or be used asa part of a front horn 1702, a front rail 1704, a front side rail 1706,a rear side rail 1708, a rear rail 1710, and/or as one or more crossmembers 1712. Likewise, FIG. 18 illustrates an exemplary embodiment of avehicle upper body 1800 with several components for which thestrengthening can be used. For example, the strengthening members inaccordance with the present disclosure may be formed or be used as apart of a shotgun 1802, a hinge-pillar 1804, an A-pillar 1806, aB-pillar 1808, a C-pillar 1810, one or more door beams 1812, a cross carbeam 1814, a front header 1816, a rear header 1818, a cow top 1820, aroof rail 1822, a lateral roof bow 1824, longitudinal roof bow 1826, oneor more body cross members 1828, and/or a body cross member 1830.

Moreover, the strengthening members in accordance with the presentdisclosure may be used as or form a part of vehicle underbodycomponents, for example, as a rocker and/or one or more underbody crossmembers. Also, the strengthening members in accordance with the presentdisclosure may be used as or form a part of vehicle engine compartmentcomponents, for example, as one or more engine compartment crossmembers.

Depending on the application, embodiments of the present teachings willhave varied shapes (i.e. various cross sections) to accommodate specificmember space constraints. When used as a vehicle front rail, forexample, to achieve optimized axial crush performance, the lengths andthicknesses of the sides and/or angles of the corners can all beadjusted (tuned) to provide optimal strength, size and shape to meetengine compartment constraints.

Although various exemplary embodiments described herein have beendescribed as configured to be used with automotive vehicles, it isenvisioned that the various strengthening members in accordance with thepresent teachings may be configured for use with other types of vehicles(e.g. aircrafts, spacecrafts and watercrafts) and/or structures, forwhich it may be desirable to provide increased crash energy absorption.Thus, it will be appreciated by those of ordinary skill in the arthaving the benefit of this disclosure that the present teachings providestrengthening members for various applications. Further modificationsand alternative embodiments of various aspects of the present teachingswill be apparent to those skilled in the art in view of thisdescription.

It is to be understood that the particular examples and embodiments setforth herein are non-limiting, and modifications to structure,dimensions, materials, and methodologies may be made without departingfrom the scope of the present teachings.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the written description and claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present invention. At the very least, andnot as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldat least be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the present teachings are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements. Moreover, all ranges disclosedherein are to be understood to encompass any and all sub-ranges subsumedtherein.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the,” include plural referents unlessexpressly and unequivocally limited to one referent. As used herein, theterm “include” and its grammatical variants are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that can be substituted or added to thelisted items.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the devices and methods ofthe present disclosure without departing from the scope of itsteachings. Other embodiments of the disclosure will be apparent to thoseskilled in the art from consideration of the specification and practiceof the teachings disclosed herein. It is intended that the specificationand embodiment described herein be considered as exemplary only.

In particular, those skilled in the art will appreciate that astrengthening member may include more than one longitudinal section orportion, with each section or portion having one or more of thevariations taught in accordance with the present disclosure. Saidvariation(s) can be made continuously or intermittently along the lengthof each longitudinal section. In other words, strengthening members thatembody combinations of one or more of the above variations to thedisclosed tunable parameters, which have not been illustrated orexplicitly described, are also contemplated.

What is claimed is:
 1. A strengthening member for a motor vehicle, thestrengthening member comprising a sixteen-cornered cross sectionincluding sixteen corners and including sides and corners creating eightinternal angles and eight external angles, wherein each internal angleranges between about 90° and about 145°, and wherein each external angleranges between about 95° and about 175°.
 2. The strengthening member ofclaim 1, wherein each of the eight internal angles is substantially thesame.
 3. The strengthening member of claim 1, wherein each of the eightexternal angles is substantially the same.
 4. The strengthening memberof claim 1, wherein at least one internal angle is a right angle.
 5. Thestrengthening member of claim 4, wherein each of the internal angles isa right angle.
 6. The strengthening member of claim 1, furthercomprising at least one recessed portion.
 7. The strengthening member ofclaim 6, wherein the at least one recessed portion is defined by twointernal angles and two external angles of the strengthening member. 8.The strengthening member of claim 7, wherein the two external anglesdefining the recessed portion are adjacent to one another.
 9. Thestrengthening member of claim 8, wherein the two external anglesdefining the recessed portion are the same.
 10. The strengthening memberof claim 8, wherein the two internal angles are each greater than 90degrees.
 11. The strengthening member of claim 6, wherein the at leastone recessed portion is defined by three sides of the strengtheningmember.
 12. The strengthening member of claim 11, wherein the threesides of the strengthening member defining the at least one recessedportion have the same length.
 13. The strengthening member of claim 11,wherein two of the three sides of the strengthening member defining theat least one recessed portion have the same length and the other of thethree sides has a different length.
 14. The strengthening member ofclaim 6, wherein the at least one recessed portion comprises fourrecessed areas, wherein each recessed area extends along a length of thestrengthening member from a first end of the strengthening member to asecond end of the strengthening member.
 15. The strengthening member ofclaim 1, wherein the corners of the cross section have substantially thesame thickness as the sides of the cross section.
 16. A strengtheningmember for a motor vehicle, the strengthening member comprising: a crosssection comprising sixteen corners and including sides and cornerscreating eight internal angles and eight external angles; and alongitudinal axis, wherein the strengthening member tapers along thelongitudinal axis.
 17. The strengthening member of claim 16, whereineach internal angle is adjacent to another internal angle and anexternal angle.
 18. The strengthening member of claim 17, wherein thecross section has more than two bisecting planes of symmetry.
 19. Thestrengthening member of claim 18, wherein the cross section has fourbisecting planes of symmetry.
 20. The strengthening member of claim 16,wherein at least one internal angle of the cross section varies along atleast a portion of a length of the strengthening member.
 21. Thestrengthening member of claim 16, wherein a thickness of at least oneside of the strengthening member varies along at least a portion of alength of the strengthening member.
 22. A vehicle comprising: astrengthening member comprising a sixteen-cornered cross sectionincluding sixteen corners and including sides and corners creating eightinternal angle corners and eight external angle corners.
 23. The vehicleof claim 22, wherein the strengthening member is, or is within, at leastone vehicle structural member selected from the group consisting of: acrush can, a front horn, a front rail, a front side rail, a rear siderail, a rear rail, a frame cross member, a shotgun, a hinge-pillar, anA-pillar, a B-pillar, a C-pillar, a door beam, a cross car beam, a frontheader, a rear header, a cow top, a roof rail, a lateral roof bow,longitudinal roof bow, a body cross member, a back panel cross member, arocker, an underbody cross member, and an engine compartment crossmember.